In many if not most buildings designed specifically for the presentation of entertainment, such as theaters, sports stadiums and concert halls, lighting fixtures, show curtains and the like are normally suspended from the roof of the building or an adjacent ceiling thereof. It is frequently necessary to do work on these fixtures; for example to change the angle of projection of spotlights or to effect repairs on the same or other such fixtures.
Till now the means to attend to the fixtures have consisted of walkways or screened suspended floors. The principal disadvantages of such constructions are that they are expensive to build and that the fixtures are not infrequently located in somewhat awkward positions due to their presence.